Push rod



Jan. 6, 1948. L, J. ROSA 2,434,080

` PUSH ROD Filed Nov. 5,'1945 1N V EN TOR.

Patented Jan. 6, 1&948

UNITED STATES PATENT OFFICE PUSH Ron Leonard J. Rosa, Detroit, Mich. Y Application November 5, 1945, serial No. 626,878

(C1. 12s-9o) 7 Claims.

used in valve actuating mechanisms of internal combustion engines and to a method of making the same.

An important object of the invention is to provide a push rod that is strong and rugged in construction but exceedingly light in weight.

Another object of the invention is to provide a push rod that is simple in construction and inexpensive to manufacture.

Still another object of the invention is to provide an eicient method of making the push rod.

Yet another object of the invention is to provide a novel method of capping the ends of the push rod that eiects a strong, rigid union between the caps and the terminal portions of the rod.

Other objects and advantages of the invention will be apparent during the course of the following description.

In the drawing, forming a part of this speciiication and wherein like numerals are employed to designate like parts throughout the same,

Figure 1 is a side elevation of a push rod cmbodying the invention, parts being broken away and shown in section for clearness of illustration,

Figure 2 is a side elevation of a tubular metal rod as it appears before the end caps are applied thereto,

Figure 3 is a fragmentary longitudinal sectional view through one of the end caps and a terminal portion of the tube showing the initial relationship of the parts during the capping operation,

Figure 4 is a view similar to Figure 3, but showg ing the end of the tube pressed into the cap,

Figure 5 is a view similar to Figure 4, but illustrating the relationship of the parts after the tube has been pushed farther into the cap,

Figure 6 is a View similar to Figure 5 but illustrating a subsequent step in the capping operation and showing the tube expanded radially into the circumferential enlargement provided in the side wall of the cap,

Figure 7 is a vew similar to Figure 6 but illustrating the relationship of the parts during the iinal step of the capping operation and showing the tube folded or upset against the inner end of the cap,

Figure 8 is a longitudinal sectional view through a modied tube and cap showing the manner in which an oversize tube can be capped according to the present invention and illustrating the initial relationship of the parts during the capping operation, Y Y

Figure 9 is a view similar to Figure 8 but illustrating the relationship of the tube and cap after 2 the capping operation has been completed, and Figure 10 is a longitudinal sectional view through a second ymodied tube and cap and showing the relationship of the parts after the nal capping operation.

Considered in certain of its broader aspects, the

` invention comprises a push rod of the type shown in my copending application, Serial No. 548,267, which was led August 5, 1944. However, the pushV rod embodying the instant invention diiers .structurally from the push rod" shown in the application and it is formed by an entirely different method. According to the present invention, the terminal portions of a tubular metal rod are inserted Y in preformed caps of relatively harder material andthe parts subjected to an axially compressive force. The sockets of the caps are provided with spherically curved bottom portions and circumferential enlargements in at least a portion of their side Walls so that application of force in the.

the tube to further deformation becomes suffi-4 ciently great, its side wall expands radially intoy the circumferential enlargements. Continued application-of pressure then causes the portions of the tube extending from the caps to fold outwardly or upset against the inner ends of the caps. Preferably, the inner ends of the caps are then. compressed slightly to assure a snug, tight t with the tube. YThe capping operation is completed and the caps are strongly and rigidly united with the tube.

Obviously, there are a number of different ways in which the tube and caps can be mechanically held or supported during the capping operation; however, this conveniently may be done by gripping the tube immediately behind the point at which the iinal upset occurs and then pressing the caps toward each other whereby to subject the rod to an axially compressive force The tube preferably is held mechanically by suitable gripping jaws and pressure is applied to the caps in any suitable manner such as by mechanically or hydraulically driven rams. Y

This method of forming the push rod permits the finished product to be held to an accurate longitudinal dimension. If the jaws which grip the tube are accurately and uniformly spaced,

all the .push 4rods will be brought tothe same 2,434, 3 longitudinal dimension since the nal upset occurs in the portion of the tube extending between the end of the cap and the jaws. The method of forming the tube is such that it can be made automatically by mechanical means.

In practice, the caps are first formed, then hardened and preferably brought to an externally highly nished condition before they are applied to the tubes. Since the caps are small they kcan be economically manufactured Vandqr'eadily han:-` dled. The capping operation preferably is done' cold so as not to affect the finish of the caps.

From the foregoing it will be apparent that the push rod embodying the instant invention comer prises an elongated, relatively thin-walled metal tube which carries end caps of relatively hardL metal and having circumferential enlargements in the side walls thereof. Y

The portions of the rod within the capspress against the ends of the latter, enter the circum- 20 ferential-enlargement inI their sidewalls and'rhave' radial extrusionswhichf bear againstithefinner ends thereof; The .interlocking 'engagement thus provided :by: the deformed 'portions of thertubefY hold the caps solidly and permanently.;associated'V therewith: .4 n

Forya'inore detailed :description ofthe invention; reference isy had tof the iaccomp'anying; drawingwhereinf'the numeral 'Zfdesignates-a .tubular` met-alI rod; 'andithe numerals 22 land :24vdesignater caps on thefends'ofwtherrod. The rod Zl is 4formed fromi any suitable thin-walled tubing of'sufcient strength to sustain the stresses to which'it will be;subjected;finiuse,. and the caps v22 'and 24 -are formedsifrom afhardenable steelo-r other-suitable metal; which.' iisA relatively stronger zthanr -the rod; EachLof-ithescaps isifpreformed andihas 'a' spherii callyrcurved convexend `portion 26 provided with an"oi1;opening,. 23 and aacylindrical 'side' wall .Sllf providediinterrnedi'ate its :ends withi aprCumferenti-fallenlargement '32."

If the .,rodr'is of relatively small diameter; 'the 'f compositie f push rod. is preferablyormed rinvtheVl manner-illustrated in ligures,Z3-57i. A suitable tu`a bula'rnrod :2G somewhat 'shorterfthan the: nished produ'ctiis selected .and placedfbetween suitable'` gripping i jaws i (now shown D., which'rengage eit'att accurately fspaced; predetermined; points;` The i capsiZZ and Zliare then applied-Ito the projecting: portions ofthe rod, las shown ini Figure 3." These caps-may fbeapplied either :singularly :or: vsimuli-A taneously; howevenfin `the interest of brevity `andi clarity;thedescriptionfwill be llimitedito the "manner'liri.` which cap 22S onlydisi'applie'd.' Itxwillibeiunderstood that,A in Ipractican'iti is; contemplated: 551

that both'- of the caps may 'be applied in 1 the same f. manner andatthesame time..

The cap 22 can easily be pushedontothef-tubef 20`to the -position shown inrligureluy Tlie'ftube ts *snugly 1in the mouthportionl `3i! fandf passes.'r 50: readily' throughI .the circumferentially enlarged portionfr'et' However; the portionfSUof the 'sidezfi walll-'behindenlargement .'iZ-is slightly Ismaller' than't-h'e externalY diameter vof -thegtiibe =and=conesiderable pressure must be appliedto the "cap fto: 65 f 4 4 gressively forced onto the tube 20, the resistance offered by the latter becomes greater. When the resistance is sufliciently great, the tube 20 yields at the point 42 where it enters wall portion 38 and expands radially against the circumferentially enlarged wall portion 36. The expanded portion of the tube is designated by the numeral 44 and, as shown in Figure 6, it closely follows the outline of the enlargement and is pressed solidly against 'the ywall offthe latter:

As'"soon"as 4the'tube expands radially in the manner hereinabove described, resistance to further movement of the cap 22 becomes so great that the portion of the tube extending between the cap and the gripping jaws upsets, as at 46, against-i-thelinner end of the cap. This step is showninvFigureF and, as soon as it occurs, the capping operation is complete.

Inl practice, the entire operation can be performed rapidly and with very little danger of damageftoftheffparts. f Theinterlocking engagements between fthe-cap and the` rod iholds the` former. solidly` united: with the tube,-

If it is necessary or desirable to make the Jtubej f 20=-stronger and vrelatively larger in diameter as show-nA inT Figures ySfand9;th'e'fen`d caps 22 and124 are preferably maintainedfsmall inY order yto'minimize.the.weight xoffthepush: rod:l Therefore, theiends 'offtherod Yare spunvdown or other-wise reduced in diameter to vprovide--terminals'llof substantiallyfthe-A same f diameter 'as .the 'internal annularv surfaces `3ft-of fthe-caps; li8-are1joined 'to-` the tube' 2 by annular Atapered shoulders' 5S and th'ewmouthsl fof ther caps are made slightly :larger inf diam eter .thanthe externaldiameter fof the-tube; Thus, when :the 4tube is held: and: lithe''oaps 4:22 and' `2d lapplied thereto' in the -mannerly hereinabove described with: reference to the first form of the invention, a snu'g'for'lightY pressffit'isfprovided betweenthe terminals 48 andzithe'cyl-indri'cal `wall portions 138: When the annular shoulders? 50 Aengage `the .inner ztapered surfaces'of the circumferential renlargements 35,

theyiprovidesuflicient resistance so thatV the tube i expands'radiallytinto'fthe-:enlargements andupr setsfagainstl ,ther inner .fedgesy of `the caps best shown'inrFigure 9.5

As suggested, the push rod construction shown;

in;` vFigures andi 9 conveniently 'may be' used whenever: it is'necessary orHdesirable Ato'employ arelativelyzlargef-irod' Zllbut undesirable corre; spondingly'to 'increase "the `rsize 'and weight. of end capsr22l=anda 211;. By: maintaining the end caps small, a -.substantialsaving :1in .weightfresults and tnisiis arr exceedingly important factor'fin a 'de- Vice fofiftliis character.'v

Reference isv now #had'to-Figure 10 which. shows amodieditypeof;endicap. 1 Inirthis form ofthe invention, ztheiend cap is designated by the .nu-

merala 2= 'and is provided with aispherica'lly fcurve'd," concaveenduvallf'and an inwardly tapered cy:. lindrical side wall 5&5. In .the enclwall'ilfisian;`

culatethrough sthefpushz rod and :'to :the bearings at :eaohiendcthereofinxthe'econventional mannersV i The-mouth ileof capl Ea snugly receives the tube 29 and the cap can be easily pushed on the tube-i miti-lathe -flatterw engages 'fthe 'endffe Continued axialfpress-ure'againstrthefcap ,pwhile maintaim. l 1, inguthe :tube-*2 @stationary inithe manner,Y herein;` f above i.described;i causes the` 'innerisphericalf sur` faceffof:*fthe*` end: 54 :to sspreadi'the' -tubeu'solidly against the wall 5% and the portion of vthee'tube;

extending. between the 'capiandtheclamping fjaws tof-.upset-yas wat :529i against =therinnerrend of lthe e The terminalsV cap. It will be observed that the spread DOItiOn 0f the tube 20 which seats solidly against the inner surface of wall 53 cooperates with the upset portion 62 to hold the cap 52 rmly united with the tube.

It is to be understood that the form of the invention herewith shown and described is to be taken as a preferred example of the same and that various changes in the size, shaper and arrangement of parts may be resorted to without departing from the spirit of the invention or the scope of the appended claims.

Having thus described the invention, I claim:

1. An engine push rod comprising an elongated rod, and a cap on at least one end of the rod, the side Walls of said cap being circumferentially enlarged intermediate its ends, the portion of the rod in said cap entering said enlargement and the portion of the rod extending from and immediately adjacent to the cap being circumferentially enlarged and bearing against the end of the cap.

2. An engine push rod comprising an elongated rod, and caps on the ends of the rod, the side Walls of each cap being circumferentially enlarged intermediate its ends, the portions of the rod in said caps entering said enlargements and the portions of the rod extending from and immediately adjacent to the caps being circumferentially enlarged and bearing against the ends of the caps.

3. An engine push rod comprising an elongated relatively thin-walled metal tube, and caps on the ends of the tube, the side Walls of each cap being circumferentially enlarged intermediate its ends, the portions of the rod in said caps having radial extrusions which enter the enlargements of said caps, and the portions of the rod extending from but immediately adjacent to the caps having radial extrusions which bear against the ends of the caps, said extrusions within the caps and said extrusions outside the caps coacting to hold the caps securely on the terminal portions of the rod.

4. An engine push rod comprising an elongated relatively thin-walled metal tube, and caps on the ends of the tube, each of said caps having a spherically curved end portion and being circumferentially enlarged intermediate its ends, the ends of the rod seating solidly against the ends of the caps, said rods also provided with radial extrusions which enter the circumferential enlargements and additional radial ext-rusions which bear against the inner ends of the caps.

5. An engine push rod comprising an elongated relatively thin-walled metal tube and a cap on the end of the tube, said cap having a convex outer end and being circumferentially enlarged intermediate its ends, the end of the rod within said cap being curved inwardly and seating solidly against the end of the cap, said rod also provided with a radial extrusion which ts snugly within the circumferential enlargement and a separate radial extrusion which bears against the inner end of the cap.

6. An engine push rod comprising an elongated relatively thin-walled metal tube, and a cap on the end of the tube, the outer end of said cap being concave and the side wall thereof being in.. Wardly tapered, the end of the tube seating solidly against the end of the cap and the terminal portion of the tube being flared and seating solidlir against the side wall of the cap, and a radial extrusion in said rod bearing against the inner end of the cap and coacting with the ared terminal portion thereof to hold the cap securely on the rod.

7. An engine push rod comprising an elongated rod, and a cap on at least one end of the rod, the side walls of said cap having a radially enlarged portion spaced axially from the inner end thereof, a portion of the rod in said cap entering said radially enlarged portion and a portion of the rod extending from and immediately adjacent to the cap being circumferentially enlarged and bearing against the end of the cap.

LEONARD J. ROSA.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,050,422 Birchwood Jan. 14, 1913 1,719,243 Shaft July 2, 1929 1,823,419 Almen Sept. l5, 1931 528,167 Jones Oct. 30, 1894: 2,324,142 Eklund July 13, 1943 

